Genome duplication within the B. napus genome relative to five Arabidopsis chromosomes. Each dot represents an alignment between a genetic marker of B. napus and its homology BLAST hit within Arabidopsis chromosomes. i) the Arabidopsis blocks used in Parkin et al. , ii) the ancient karyotype (AK) blocks from Schranz et al.  are shown alongside the dot-plots aligned to their Arabidopsis chromosomal positions.